The answer to 'dryer vent odor' is that the most common causes are lint buildup, mold or mildew, or a blocked or damaged vent. Symptoms include a musty or burning smell coming from the dryer vent, and the dryer taking longer to dry clothes. Solutions include cleaning the vent, repairing any damage, and ensuring proper airflow.
If the odor persists or you're unable to locate and fix the issue, it's best to call a professional cleaning technician. They have the tools and expertise to thoroughly inspect and clean the dryer vent system, identify the root cause, and make any necessary repairs.